I ordered "SnapMedia" software plus a cable from "FutureDial" (futuredial.com).
The cable # I ordered is #3 on their site (for the SCH-A790). It connects to your PC's USB port (it's a USB->serial adapter). Here's a link to the cable: http://www.futuredial.com/FDCart/ProductDetai ls.aspx?pid=707&cid=50
(I don't know if the cable will work with any 'standard' software out there, or just things like FutureDial's SnapMedia).
I've only just started messing with the SnapMedia software. I successfully sent some jpegs from my PC to the phone, and some photos taken on my phone back to my PC.
It doesn't look like you can download ringtones from the phone - you can only send MIDI ringtones *to* the phone (I haven't tried this yet).
FutureDial?? I would not buy it if I were you. This company's product is expensive and the feature is very limited. Why don't you try Datapilot or Handset Manager(mobile action)? They have better solutions for your phones. But if you want a product that comes with great features and resonable price,you might need to go for Handset Manager though.